Local iron homeostasis in the breast ductal carcinoma microenvironment. Issue 1 (December 2016)

• Record Type: Journal Article
• Authors: Marques, Oriana; Porto, Graça; Rêma, Alexandra; Faria, Fátima; Cruz Paula, Arnaud; Gomez-Lazaro, Maria; Silva, Paula; Martins da Silva, Berta; Lopes, Carlos
• Is Part Of: BMC cancer. Volume 16:Issue 1(2016)
• Page Start: 1
• Page End: 14
• Publication Date: 2016-12
• Subjects: Breast cancer -- Ferroportin 1 -- Iron -- Stromal inflammatory cells -- Tissue microenvironment; Cancer -- Periodicals; 616.994005
• DOI: 10.1186/s12885-016-2228-y
• Languages: English
• ISSNs: 1471-2407

Abstract

Abstract Background While the deregulation of iron homeostasis in breast epithelial cells is acknowledged, iron-related alterations in stromal inflammatory cells from the tumor microenvironment have not been explored. Methods Immunohistochemistry for hepcidin, ferroportin 1 (FPN1), transferrin receptor 1 (TFR1) and ferritin (FT) was performed in primary breast tissues and axillary lymph nodes in order to dissect the iron-profiles of epithelial cells, lymphocytes and macrophages. Furthermore, breast carcinoma core biopsies frozen in optimum cutting temperature (OCT) compound were subjected to imaging flow cytometry to confirm FPN1 expression in the cell types previously evaluated and determine its cellular localization. Results We confirm previous results by showing that breast cancer epithelial cells present an 'iron-utilization phenotype' with an increased expression of hepcidin and TFR1, and decreased expression of FT. On the other hand, lymphocytes and macrophages infiltrating primary tumors and from metastized lymph nodes display an 'iron-donor' phenotype, with increased expression of FPN1 and FT, concomitant with an activation profile reflected by a higher expression of TFR1 and hepcidin. A higher percentage of breast carcinomas, compared to control mastectomy samples, present iron accumulation in stromal inflammatory cells, suggesting that these cells may constitute an effective tissue iron reservoir. Additionally, not only the deregulated expression of iron-related proteins in epithelial cells, but also on lymphocytes and macrophages, are associated with clinicopathological markers of breast cancer poor prognosis, such as negative hormone receptor status and tumor size. Conclusions The present results reinforce the importance of analyzing the tumor microenvironment in breast cancer, extending the contribution of immune cells to local iron homeostasis in the tumor microenvironment context.